(Patagonia’s Untold Stories)

While packrafting the southeastern edge of the Northern Patagonia Ice Field along Chile’s largest river, the Baker, in search of primitive crane flies, Anand Varma and I came across an exciting find.

In a fragmented location only accessible via water, among a lichened-covered forest, we discovered a single wing of the genus Neoderus adhered to the underside of a leaf, between the Northern and Southern Ice Fields. Yes, a single wing is a fantastic find when it comes to primitive crane flies.

Most likely you have never heard of them and that is because primitive crane flies are considered to be one of the rarest groups of flies in the world and only a handful of people have been able to collect them. With only one specimen ever collected in the late 1800s in the southern Chilean fjords, the genus Neoderus can be considered the rarest of all primitive crane flies.

During my last expedition in 2015 I secured four flies, the first and only specimens collected of this genus since its discovery.

With colder temperatures marking the last chance this year to find this rare group, I set off once again to complete what Anand and I started. I decided to target the locality where I found a lone wing two years prior. I loaded my backpack, took my hiking poles (or as my collaborators call them, “my gimpy sticks”, due to the frequency of my ankle injuries) and limped into one of the most pristine creeks I have seen. After a 1100ft climb and bushwhacking across dense forest I arrived to the location.

Upon arrival I removed my hiking boots and proceeded to relieve my ankle pain in the glacial creek. Soon after, I unpacked my 60+lb backpack and identified the perfect configuration for my tree tent, which was strategically located near the creek 6ft above the ground. Below my tent, I set up my “field laboratory” consisting of a stereomicroscope from the early 1980s with generic USB lights secured by duct tape and powered via rechargeable solar battery. This arrangement allows me to collect aquatic insects and immediately identify any promising specimen under high magnification. The dream camp set up of any insect-loving seven-year-old!

Not only does my tree tent provide a dry refuge from sudden rainfall, characteristic to this area, but it is also the perfect barrier from the numerous avian intestinal discharges I am constantly being bombarded with by territorial birds.

With sunset approaching, I decided to have something to eat. I packed all the necessary gear for this short expedition but managed to forget food.

Loose in one of my backpack’s hipbelt pockets, I found a handful of stale trail mix (from sometime since September) and a piece of chocolate.

Lack of aesthetically pleasing or “proper” camping food, seem to be a trend for this site. A couple of years ago, my food bag punctured and got wet while reaching this exact location, leaving me to consume lukewarm soft cheese, soggy bread and broken crackers accidentally blended into a paste-like consistency. Read more about this particular story here.

This time was no different. As I searched the creek looking for the unknown larvae of Neoderus and other aquatic insects, I intentionally separated the largest common stoneflies. I later proceeded to make my “back-country specialty” of au naturel stonefly and stale raisin kebabs on endemic southern beech twigs, complemented with all-you-can-drink glacial melts. A true delight! My other options were: 1) No food or 2) Soggy almonds and common black fly larvae, but the latter are quite slimy and a last resort among the edible insect choices on my list.

With hunger “satisfied”, I set up my blacklight a few feet away from the stream. While waiting for insects to be attracted to the light reflected on a white sheet, I set off into the dark forest in true nerd-like fashion with my rain pants synched up to my mid abdomen, my cuffs tucked into my socks and sporting my night vision goggles in search of nocturnal six-legged gems.

Throughout the night, the UV light attracted all sorts of insects, including Darwin’s beetles, half-inch-long parasitic wasps, caddisflies, moths and many midges. Alas, no Primitive Crane Flies.

Soon after midnight, rain drove away most of the insects and continued to pour until mid-morning. With sunrise approaching and a sufficient few hours of sleep, I climbed out of bed, ate a forgotten stonefly still in the “food” container and the piece of chocolate for breakfast, put on my rain gear and limped across the forest in search of the insect I came for.

After wadding through the creek for a couple of hours with no success, I decided to direct my attention to the numerous fallen trees around the forest. Interestingly, a large decaying tree still hangs 8ft high over the creek. Underneath, a Neoderus female. After squealing like a piglet for some time, I proceeded to secure the specimen. Crane flies in general are well known among taxonomists to lose or detach their legs at will. This particular female had all six legs still attached, making it the only pristine specimen in the world.

With my precious find, I headed straight back to camp. Once there, I frantically packed it all up and awkwardly limped back to my vehicle a few miles away, all the while juggling the specimen, my heavy backpack and my “gimpy sticks”.

I drove eight hours back to my headquarters and proceeded to photograph the female. After a long and continuous photography session of 48hours the female finally died, but not before yielding the photographs above. These, along with one poor quality image from 2015, are the only photographs of a live Neoderus in existence. A true reminder of the biological jewels awaiting discovery in the vicinities of the Patagonia Ice Fields.

Climate change has spurred the spread of invasive insects that devour crops, destroy homes, and spread disease. Now, rising temperatures are driving cadaver-eating blow flies to migrate north in search of cooler weather, with consequences for forensic scientists who rely on them to solve crimes.

Blow flies are drawn to dead bodies, both human and animal. They land on a fresh corpse within minutes of death. The females take a quick taste to make sure it’s good food for their larvae, then lay hundreds of eggs. Once hatched, the maggots begin feasting on soft tissues, hastening decomposition. In doing so, they become key players in murder investigations by helping forensic scientists determine when a person died. Blow flies have proved critical in countless homicides by supporting the innocence or guilt of suspected killers.

Forensic entomologists can do this because they know the lifecycle of blow flies found in their region. But now, as blow flies move northward, driven by rising temperatures to find more comfortable homes, these death inquiries could become flawed as newcomers who resemble resident blow flies produce offspring that grow on a different schedule.

Lucilia cuprina, more commonly known as an Australian sheep blow fly. Photo: fir0002

In the Midwest, for example, a new type of blow fly species — one that typically lives in southern states — has taken up residence. Lucilia cuprina has been spotted in parks and other public places more than two dozen times in Indiana between 2015 and 2017. It looks a lot like its sister species, Lucilia sericata, which is widely present in the state, but its maggots don’t act the same. Mistaking one for another could cause big headaches for crime solvers.

“The larvae of both species are difficult to tell apart, thus it’s possible a forensic investigator might end up with an inaccurate time of death,” said Christine Picard, associate professor of biology at Indiana University-Purdue University Indianapolis School of Science. “If, for example, a maggot is identified as L. sericata but actually is L. cuprina, the time of death could be an underestimate. Different species will have different development times. This could have implications involving decomposing remains. Forensic scientists need to be aware that this new species is present so they don’t make this mistake.” Picard, who studies the behavior of blow flies around the world, said a member of her lab first identified the migrant blow fly several years ago.

Blow flies. Photo: Journal of Insect Science

“It was a blow fly in Indiana that we hadn’t seen before, and so we have been paying attention,” she said. “We do a ton of fly collection — catching blow flies is easy, all you need is a container of rotten meat and a fly net — and it was like ‘holy cow, what are you doing here?’ This species is pretty well known in Florida and Texas, where I have colleagues I speak with regularly, but here in Indiana, it was unexpected. In this particular case, a PhD student was out doing her normal collections — she would go out every two weeks during the summers, collecting from around Indianapolis for her dissertation work — and as she was identifying them, she noted [the interloper species].”

Picard and her colleagues recently published a paper describing the appearance of this blow fly in Indiana, which appeared in the Journal of Insect Science. “As temperatures change and increase, the distribution of these insects will continue to change as well,” Picard said. She predicts blow flies will continue to migrate northward in search of cooler climates and new sources of food.

Rest assured that, while blow flies may be unpleasant, they don’t bite and, “other than the accidental deposit of bacteria from their feet possibly getting onto some food you might be eating,” they don’t transmit diseases, Picard said. “They act primarily as nature’s recyclers, not causing any real damage.”

Lucilia sericata, commonly known as a greenbottle fly. Photo: Calibas

“Blow flies live in a really competitive environment. They need a very valuable resource — a dead animal — to survive, so they compete with other blow flies and with scavengers,” she said. “Their ability to find a dead animal and grow very quickly makes them competitive. But there is a finite number of dead animals out there. So, they will continue to expand their distributions as long as they can survive.” Rising temperatures allow blow flies to extend their reach into areas that were previously too cold to inhabit.

“Forensic scientists should be aware, but everyone should care,” Picard said, noting that while blow flies are largely harmless, other species are not. “Even though these particular flies don’t carry disease, many others do. If they are expanding their ranges, there is no doubt other insects are as well.”